/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.commons.exec;

import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.exec.util.DebugUtils;

/**
 * Copies all data from an System.input stream to an output stream of the executed process.
 */
public class InputStreamPumper implements Runnable {

    /**
     * Sleep time in milliseconds.
     */
    public static final int SLEEPING_TIME = 100;

    /** The input stream to pump from. */
    private final InputStream is;

    /** The output stream to pmp into. */
    private final OutputStream os;

    /** Flag to stop the stream pumping. */
    private volatile boolean stop;

    /**
     * Create a new stream pumper.
     *
     * @param is input stream to read data from.
     * @param os output stream to write data to.
     */
    public InputStreamPumper(final InputStream is, final OutputStream os) {
        this.is = is;
        this.os = os;
        this.stop = false;
    }

    /**
     * Copies data from the input stream to the output stream. Terminates as soon as the input stream is closed or an error occurs.
     */
    @Override
    public void run() {
        try {
            while (!stop) {
                while (is.available() > 0 && !stop) {
                    os.write(is.read());
                }
                os.flush();
                Thread.sleep(SLEEPING_TIME);
            }
        } catch (final Exception e) {
            final String msg = "Got exception while reading/writing the stream";
            DebugUtils.handleException(msg, e);
        }
    }

    /**
     * Requests processing to stop.
     */
    public void stopProcessing() {
        stop = true;
    }

}
